The BADERC Transgenic Core (PI ? Bradford Lowell, BIDMC) is a fee-for-service facility that takes investigator-derived DNA constructs or investigator derived (or obtained) genetically modified embryonic stem (ES) cells to create founder transgenic and gene knockout or gene knockin mice (i.e. mice bearing point mutants, lox-modified or ires/2A-Cre knockin alleles) that can be used to address questions relevant to diabetes, obesity, and nutrition, including questions related to brain control of feeding, metabolism, glucose homeostasis and hunger / reward. The Transgenic Core is heavily utilized. In the last 5 year cycle (2009-2014), the Core performed 144 projects (37 transgenic DNA injection projects, 101 ES cell injection projects and 6 cryopreservation and in vitro fertilization projects). This represents a 2.9-fold and 1.6-fold increase, respectively, in the number of projects performed during the prior 1999-2004 (50 projects) and 2004-2009 (92 projects) cycles, demonstrating progressively increasing, substantial demand for BADERC Transgenic Core services. Mice generated by the Core have had a major impact on science. In the last 5 year cycle (2009-2014), BADERC Transgenic Core- generated mice have been featured in 317 publication (131 authored by BADERC Core users and 186 authored by ?non users?, the latter demonstrating extensive sharing of BADERC Transgenic Core-generated mice with other labs). 30 of these publications were in the top tier journals, Cell, Nature and Science, and 101 appeared in other very high impact journals (Cancer Cell, Cell Metabolism, Genes & Development, J Clinical Investigation, Molecular Cell, Nature Genetics, Nature Immunology, Nature Medicine, Nature Neuroscience, Neuron and PNAS). In addition, the BADERC Transgenic Core extensively leveraged and enabled NIH Principle Investigator research grant support (in total, Core users have 55 Research NIH Grants ? by funding mechanism from most common to least ? R01, R37,R56, R24, RC2, RC4, R03 and R21). With regards to development of new technology, the BADERC Transgenic Core is evaluating and implementing CRISPR/Cas9-related approaches to engineer the mouse genome. This will further expand usage by BADERC members as it bypasses the need for gene targeting in ES cells, and consequently greatly decreases the know-how required by users and, importantly, length of time required to generate engineered mice.